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Effective Removal of Methylene Blue by Mn3O4/NiO Nanocomposite under Visible Light. SEPARATIONS 2023. [DOI: 10.3390/separations10030200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Wastewater treatment is indispensable as wastewater can lead to adverse health effects and deteriorate the quality of life on earth. Photocatalysis is a facile methodology to address this issue. In this study, nanocomposites (NCs) of manganese oxide (Mn3O4) and nickel oxide (NiO) were synthesized in different weight ratios via the solid-state reaction route. Structural properties, optical properties, surface morphology, and functional group analysis of the synthesized nanomaterials were conducted using X-ray diffraction (XRD), UV– Vis spectroscopy, scanning electron microscopy (SEM) along with energy-dispersive X-ray (EDX) analysis, and Fourier-transform infrared (FTIR) spectroscopy, respectively. The bandgap of the nanocomposite decreases significantly from 2.35 eV for the Mn3O4 NPs to 1.65 eV for the Mn3O4/NiO nanocomposite (NC). Moreover, adsorption studies followed by the photocatalytic performance of the Mn3O4/NiO NCs were evaluated to determine the removal of methylene blue (MB) dye from wastewater. The photocatalytic performance of the nanocomposite enhances as the ratio of Mn3O4 in the composite increases from one weight percentage to three weight percentage. The photocatalytic degradation efficiency was calculated to be 95%. The results show that the synthesized NCs could play an important role in photocatalytic wastewater purification and environmental remediation.
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Taheri M, Fallah N, Nasernejad B. Comparison of high-concentration azo dye removal by long HRT in MSBRs' bioaugmented with GAC and sponge media. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:1201-1215. [PMID: 35915305 DOI: 10.1007/s11356-022-22055-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 07/12/2022] [Indexed: 06/15/2023]
Abstract
The present study assessed the performance and fouling of adding granular activated carbon (GAC) and sponge (BioCube), as two different media, to a membrane sequencing batch reactor (MSBR) system in wastewater treatment containing Acid Red 18 (AR 18). Anaerobic phase, aerobic phase, and hydraulic retention times (HRTs) of 24 h, 12 h, and 72 h were considered for 500 mg/L AR 18 removal at a sludge retention time (SRT) of 20 days by separately adding up to 35% BioCube volume and 8 g/L GAC to the reactors. Based on the kinetic study, 63 mg/L (87% removal) and 115 mg/L (77% removal) remaining dye were reported in the GAC and BioCube membrane sequencing batch reactors (GAC-MSBR and BioCube-MSBR), respectively. A gradual oxidation-reduction potential decline toward -416 mV confirmed better dye removal in GAC-MSBR than BioCube-MSBR, observing a sudden drop to -354 mV. The morphology can explain better biological treatment in GAC-MSBR in addition to the adsorption process. Soluble microbial products (SMPs) of 126.92 mg/L and 395.18 mg/L were obtained for GAC-MSBR and BioCube-MSBR, respectively. Chemical oxygen demand (COD) and SMP indicated that the GAC-MSBR water quality is better than that of the other reactor.
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Affiliation(s)
- Mahsa Taheri
- Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran, 15875-4413, Iran
| | - Narges Fallah
- Chemical Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran, 15875-4413, Iran.
| | - Bahram Nasernejad
- Chemical Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran, 15875-4413, Iran
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Reynaert E, Gretener F, Julian TR, Morgenroth E. Sensor setpoints that ensure compliance with microbial water quality targets for membrane bioreactor and chlorination treatment in on-site water reuse systems. WATER RESEARCH X 2023; 18:100164. [PMID: 37250292 PMCID: PMC10214293 DOI: 10.1016/j.wroa.2022.100164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 12/13/2022] [Accepted: 12/25/2022] [Indexed: 05/31/2023]
Abstract
Widespread implementation of on-site water reuse systems is hindered by the limited ability to ensure the level of treatment and protection of human health during operation. In this study, we tested the ability of five commercially available online sensors (free chlorine (FC), oxidation-reduction potential (ORP), pH, turbidity, UV absorbance at 254 nm) to predict the microbial water quality in membrane bioreactors followed by chlorination using logistic regression-based and mechanism-based models. The microbial water quality was assessed in terms of removal of enteric bacteria from the wastewater, removal of enteric viruses, and regrowth of bacteria in the treated water. We found that FC and ORP alone could predict the microbial water quality well, with ORP-based models generally performing better. We further observed that prediction accuracy did not increase when data from multiple sensors were integrated. We propose a methodology to link online sensor measurements to risk-based water quality targets, providing operation setpoints protective of human health for specific combinations of wastewaters and reuse applications. For instance, we recommend a minimum ORP of 705 mV to ensure a virus log-removal of 5, and an ORP of 765 mV for a log-removal of 6. These setpoints were selected to ensure that the percentage of events where the water is predicted to meet the quality target but it does not remains below 5%. Such a systematic approach to set sensor setpoints could be used in the development of water reuse guidelines and regulations that aim to cover a range of reuse applications with differential risks to human health.
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Affiliation(s)
- Eva Reynaert
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Flavia Gretener
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Timothy R. Julian
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
- University of Basel, 4055 Basel, Switzerland
| | - Eberhard Morgenroth
- Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
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Hess A, Morgenroth E. Biological activated carbon filter for greywater post-treatment: Long-term TOC removal with adsorption and biodegradation. WATER RESEARCH X 2021; 13:100113. [PMID: 34611621 PMCID: PMC8476437 DOI: 10.1016/j.wroa.2021.100113] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/19/2021] [Accepted: 08/09/2021] [Indexed: 05/30/2023]
Abstract
Biological activated carbon (BAC) filters can be used to remove residual total organic carbon (TOC) from greywater after a membrane bioreactor. The two main TOC removal processes are adsorption to the granular activated carbon (GAC) and biological degradation. Biodegradation leads to the growth of microorganisms in the filter bed, which can lead to increased pressure loss over the filter bed. However, the roles of sorption and biodegradation in long-term TOC removal and how they complement each other are unclear. We monitored TOC removal from greywater in a BAC filter installed following a membrane bioreactor over more than 900 days. Removal performance depended on the operational time of the BAC filter, the influent TOC concentration, and in the upper part of the filter on the empty bed contact time (EBCT). Across the overall filter, the EBCT did not significantly influence TOC removal, showing that the filter was sufficiently large for the range of flow rates observed. Analysis of the long-term data revealed the equal importance of sorption and biodegradation over the whole operation period and the whole filter bed. Most of the TOC was removed in the upper part of the filter, where biodegradation was the dominant mechanism. In the lower part of the filter, sorption capacity remained and allowed high influent TOC concentrations to be buffered. The generous filter design with low average filtration rates ensured long-term TOC removal. The only maintenance needed was backwashing, which was required only after more than 800 days of operation. Backwashing effectively reduced the pressure loss but had no significant influence on the effluent water quality. Our study shows that BAC filters are a suitable post-treatment step for the treatment of greywater with highly variable flow and TOC concentrations.
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Affiliation(s)
- Angelika Hess
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
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Hess A, Baum C, Schiessl K, Besmer MD, Hammes F, Morgenroth E. Stagnation leads to short-term fluctuations in the effluent water quality of biofilters: A problem for greywater reuse? WATER RESEARCH X 2021; 13:100120. [PMID: 34647001 PMCID: PMC8495163 DOI: 10.1016/j.wroa.2021.100120] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 09/06/2021] [Accepted: 09/11/2021] [Indexed: 05/04/2023]
Abstract
A key characteristic of decentralized greywater treatment and reuse is high variability in both nutrient concentrations and flow. This variability in flow leads to stagnant water in the system and causes short-term fluctuations in the effluent water quality. Automated monitoring tools provide data to understand the mechanisms underlying the dynamics and to adapt control strategies accordingly. We investigated the fluctuations in a building-scale greywater treatment system comprising a membrane bioreactor followed by a biological activated carbon filter. Short-term dynamics in the effluent of the biological activated carbon filter were monitored with automated flow cytometry and turbidity, and the impact of these fluctuations on various hygiene-relevant parameters in the reuse water was evaluated. Continuous biofilm detachment into the stagnant water in the biological activated carbon filter led to temporarily increased turbidity and cell concentrations in the effluent after periods of stagnation. The fluctuations in cell concentrations were consistent with a model assuming higher detachment rates during flow than during times with stagnant water. For this system, total cell concentration and turbidity were strongly correlated. We also showed that the observed increase in cell concentration was not related to either an increase of organic carbon concentration or the concentration of two opportunistic pathogens, P. aeruginosa and L. pneumophila. Our findings demonstrate that turbidity measurements are sensitive to changes in the effluent water quality and can be used to monitor the fluctuations caused by intermittent flow. Intermittent flow did not lead to an increase in opportunistic pathogens, and this study provides no indications that stagnant water in biological activated carbon filters need be prevented.
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Affiliation(s)
- Angelika Hess
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
| | - Chiara Baum
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | | | | | - Frederik Hammes
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland
- Corresponding author.
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Jjagwe J, Olupot PW, Menya E, Kalibbala HM. Synthesis and Application of Granular Activated Carbon from Biomass Waste Materials for Water Treatment: A Review. JOURNAL OF BIORESOURCES AND BIOPRODUCTS 2021. [DOI: 10.1016/j.jobab.2021.03.003] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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Rosario P, Viswash R, Seenivasan T, Ramalingam S, Sellgren KL, Grego S, Trotochaud L. Potential Pitfalls in Wastewater Phosphorus Analysis and How to Avoid Them. ENVIRONMENTAL HEALTH INSIGHTS 2021; 15:11786302211019218. [PMID: 34103934 PMCID: PMC8168049 DOI: 10.1177/11786302211019218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/03/2021] [Indexed: 05/05/2023]
Abstract
Due to the increasing adoption of nutrient discharge regulations, many research groups are stepping into new territory with phosphorus (P) measurements. Accurate reporting of P concentrations in effluent from novel wastewater treatment technologies is critical for protecting both environmental and human health. Analysis of P in wastewater is prone to pitfalls because of the (1) variety of chemical forms of P in wastewater (orthophosphate, condensed P, and organic P), (2) availability of different chemical assays for measuring different P forms, and (3) different conventions in the units for reporting P. Here, we present a case study highlighting how these pitfalls affect analysis and interpretation of P measurements. We show that, when used appropriately, commercially-available kits are indeed accurate tools for evaluating reactive P and total P concentrations. For both standard solutions and real wastewater, we systematically remove steps from the total P protocol to show how protocol deviations affect the results. While standard solutions are important for validating analytical methods, commercially-available wastewater standard solutions only contain P as orthophosphate (reactive P). We therefore demonstrate options for making a mixed-P standard solution containing acid-hydrolyzable and/or organic P compounds that can be used to validate both reactive P and total P assays.
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Affiliation(s)
| | - Ramya Viswash
- PSG Institute of Medical Sciences and Research, Coimbatore, TN, India
| | | | - Sudha Ramalingam
- PSG Institute of Medical Sciences and Research, Coimbatore, TN, India
| | - Katelyn L Sellgren
- Center for Water, Sanitation, Hygiene, and Infectious Disease (WaSH-AID), Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Sonia Grego
- Center for Water, Sanitation, Hygiene, and Infectious Disease (WaSH-AID), Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
| | - Lena Trotochaud
- Center for Water, Sanitation, Hygiene, and Infectious Disease (WaSH-AID), Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA
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Ziemba C, Sharma P, Ahrens T, Reynaert E, Morgenroth E. Disruptions in loading and aeration impact effluent chlorine demand during biological greywater recycling. WATER RESEARCH X 2021; 11:100087. [PMID: 33665596 PMCID: PMC7898034 DOI: 10.1016/j.wroa.2020.100087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 05/04/2023]
Abstract
Greywater recycling systems designed for high-quality applications, such as hand washing, must deliver microbially safe and aesthetically acceptable water under the challenging operating conditions present where such systems are needed most urgently. As chlorination is the most popular strategy for reducing bacterial concentrations in greywater, understanding chlorination in the context of disruptive and challenging operation is essential to designing robust treatment. In this study, we have examined how disruptions through overall increased loading, interrupted aeration and increased ammonia loading have impacted the chlorine demand of the water produced by a greywater recycling system. We also presented concentrations of significant chemicals that contributed to this chlorine demand. The results indicate that a 1 d period with 8 times (8x) the normal design loading produced a peak chlorine demand of 0.74 mg Cl2/L, which is approximately double the baseline value. While this chlorine demand can be overcome by adding more chlorine, tests involving disruptions in aeration or feeding additional ammonia into the bioreactor produced much greater increases (>30x). The risks of increased chlorine demand on microbial safety can be overcome by limiting ammonia inputs to the system, providing backup systems to ensure sufficient aeration, or through additional anti-bacterial measures that do not depend on maintaining residual chlorine.
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Affiliation(s)
- Christopher Ziemba
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Pragnya Sharma
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Theresa Ahrens
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - Eva Reynaert
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
| | - Eberhard Morgenroth
- Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
- ETH Zürich, Institute of Environmental Engineering, 8093, Zürich, Switzerland
- Corresponding author. Eawag: Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland.
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Trotochaud L, Andrus RM, Tyson KJ, Miller GH, Welling CM, Donaghy PE, Incardona JD, Evans WA, Smith PK, Oriard TL, Norris ID, Stoner BR, Guest JS, Hawkins BT. Laboratory Demonstration and Preliminary Techno-Economic Analysis of an Onsite Wastewater Treatment System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:16147-16155. [PMID: 33269914 PMCID: PMC7745533 DOI: 10.1021/acs.est.0c02755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 05/21/2023]
Abstract
Providing safe and reliable sanitation services to the billions of people currently lacking them will require a multiplicity of approaches. Improving onsite wastewater treatment to standards enabling water reuse would reduce the need to transport waste and fresh water over long distances. Here, we describe a compact, automated system designed to treat the liquid fraction of blackwater for onsite water reuse that combines cross-flow ultrafiltration, activated carbon, and electrochemical oxidation. In laboratory testing, the system consistently produces effluent with 6 ≤ pH ≤ 9, total suspended solids (TSS) < 30 mg L-1, and chemical oxygen demand (COD) < 150 mg L-1. These effluent parameters were achieved across a wide range of values for influent TSS (61-820 mg L-1) and COD (384-1505 mg L-1), demonstrating a robust system for treating wastewater of varying strengths. A preliminary techno-economic analysis (TEA) was conducted to elucidate primary cost drivers and prioritize research and development pathways toward commercial feasibility. The ultrafiltration system is the primary cost driver, contributing to >50% of both the energy and maintenance costs. Several scenario parameters showed an outsized impact on costs relative to technology parameters. Specific technological improvements for future prototype development are discussed.
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Affiliation(s)
- Lena Trotochaud
- Duke
University, Center for Water, Sanitation,
Hygiene, and Infectious Disease (WaSH-AID), Durham, North Carolina 27701, United States
- Department
of Electrical & Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Rebecca M. Andrus
- Department
of Civil & Environmental Engineering, University of Illinois at Urbana−Champagne, Urbana, Illinois 61801, United States
| | - Kayana J. Tyson
- Duke
University, Center for Water, Sanitation,
Hygiene, and Infectious Disease (WaSH-AID), Durham, North Carolina 27701, United States
- Department
of Civil & Environmental Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Graham H. Miller
- Duke
University, Center for Water, Sanitation,
Hygiene, and Infectious Disease (WaSH-AID), Durham, North Carolina 27701, United States
- Department
of Electrical & Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Claire M. Welling
- Duke
University, Center for Water, Sanitation,
Hygiene, and Infectious Disease (WaSH-AID), Durham, North Carolina 27701, United States
- Department
of Electrical & Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | | | | | | | - Paul K. Smith
- Cascade
Designs, Seattle, Washington 98134, United States
| | - Tim L. Oriard
- Cascade
Designs, Seattle, Washington 98134, United States
| | - Ian D. Norris
- Cascade
Designs, Seattle, Washington 98134, United States
| | - Brian R. Stoner
- Duke
University, Center for Water, Sanitation,
Hygiene, and Infectious Disease (WaSH-AID), Durham, North Carolina 27701, United States
- Department
of Electrical & Computer Engineering, Duke University, Durham, North Carolina 27708, United States
| | - Jeremy S. Guest
- Department
of Civil & Environmental Engineering, University of Illinois at Urbana−Champagne, Urbana, Illinois 61801, United States
| | - Brian T. Hawkins
- Duke
University, Center for Water, Sanitation,
Hygiene, and Infectious Disease (WaSH-AID), Durham, North Carolina 27701, United States
- Department
of Electrical & Computer Engineering, Duke University, Durham, North Carolina 27708, United States
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